Aortic Arches and Congenital Defects

Question 1

What is the FATE of the 1st and 2nd ARCHES?

Answer 1

*Disappear Early

Remnant of 1st Arch Forms part of the MAXILLARY ARTERY (Branch of the External Carotid A.)

Question 2

What is the FATE of the 3rd ARCHES?

Answer 2

*CAROTID arch

Commencement of the Internal Carotid A.

Question 3

What is the FATE of the 4th ARCHES?

Answer 3

Right - Forms RIGHT SUBCLAVIAN A.

Left - Constitutes the Distal Part of the AORTIC ARCH

Question 4

What is the FATE of the 5th ARCHES?

Answer 4

*Either Fails to Form Completely or Regresses

Question 5

What is the FATE of the 6th ARCHES?

Answer 5

*Pulmonary Trunk

Right - Forms the Proximal Part of the RIGHT PULMONARY ARTERY

Left - Gives of the LEFT PULMONARY ARTERY and Forms the Ductus Arteriosus (which becomes obliterated and forms the Ligamentum Arteriosum)

Question 6

What is an ABERRANT SUBCLAVIAN ARTERY?

Answer 6

*Consequence of Poor Development of Arch 4

Right Subclavian Forms Lateral to the Left Subclavian, instead of becoming a Branch of the Brachiocephalic Trunk

Question 7

What PROBLEMS may an aberrant subclavian artery cause?

Answer 7

1) In order to perfuse the Right Arm it must CROSS OVER the midline behind the Trachea and Oesophagus
2) This may CONSTRICT these organs

Question 8

What would be the CONSEQUENCES of a DOUBLE aortic arch forming?

Answer 8

1) The Branched Vessel would Wrap Around the Trachea and Oesophagus
2) Causing Dyspnoea and Dysphagia

Question 9

What is PATENT DUCTUS ARTERIOSUS (PDA)?

Answer 9

Ductus Arteriosus Fails to Close After Birth

Question 10

What are the CONSEQUENCES of PDA?

Answer 10

*1st Year of Life

1) > Work of Breathing
2) Poor Weight Gain

• With > Age
  3) Congestive Heart Failure

Question 11

What is COARCTATION of the AORTA?

Answer 11

Narrowing of the Aorta; Generally Near Where the Ductus Arteriosus Inserts

Question 12

What VESSELS carry OXYGENATED BLOOD to the EMBRYO?

Answer 12

Umbilical Veins

Question 13

Which VEINS form the VENA CAVA?

Answer 13

Cardinal Veins

Question 14

What 3 STRUCTURES are VITAL for FOETAL CIRCULATION?

Answer 14

1) Ductus Arteriosus
2) Foramen Ovale
3) Ductus Venosus

Question 15

What is, normally, the FATE of these 3 structures AFTER BIRTH?

Answer 15

1) Ductus Arteriosus becomes Ligamentum Arteriosum
2) Foramen Ovale - Closes by Tissue Proliferation and Septal Adherence
3) Ductus Venosus becomes the Ligamentum Venosum (Liver)

Question 16

What is a COMMON CAUSE associated with PDA?

Answer 16

Maternal Infection during Early Pregnancy, i.e. Rubella

Question 17

What are the COMMON CAUSES of COARCTATION of the AORTA?

Answer 17

1) Incorporation of Muscle Tissue of the Ductus Arteriosus into the Aortic Arch
2) Genetic Anomalies, i.e. Turner’s Syndrome
3) Environmental Factors